JP2012071870A - Method for manufacturing composite container - Google Patents

Abstract

An object of the present invention is to provide a composite container suitable for the retort processing of contents and a manufacturing method thereof.
An inner layer side plastic molded product having a flange portion in an opening, an intermediate base material, and an outer layer side plastic molded product having a flange portion in an opening are laminated in this order to seal the intermediate base material. A method of manufacturing a composite container, wherein an intermediate base material is inserted inside an outer layer side plastic molded product, and the inner peripheral edge of the outer layer side flange portion and the opening edge of the intermediate base material are thermally bonded, and then the intermediate base material The inner layer side plastic molded product is inserted inside, and the outer layer side flange part and the inner layer side flange part are partly heat-bonded to make a composite container intermediate product. A method for manufacturing a composite container is characterized in that the gas remaining between the products is removed, and the entire intermediate product of the composite container is kept under reduced pressure, and the outer layer side flange part and the inner layer side flange part are all thermally bonded.
[Selection] Figure 2

Description

  The present invention relates to a container capable of retorting (heating and pressure sterilization) the contents, and more particularly to a method for manufacturing a container-shaped composite container that can be reheated by a microwave oven.

Most of the retortable containers currently on the market are in the form of pouches. In the case of such a pouch-shaped container, the method of use is generally heated in a hot water bath or a microwave oven, and then transferred to a dish for eating and drinking, which takes time and effort such as washing the dish after the meal.
Containers that can be retorted are also available on the market, but the material is plastic. However, it is difficult to say that a plastic container is desirable from the environmental aspect of reducing carbon dioxide emissions.

  In contrast to containers made of plastic as a raw material, containers made of paper as the main raw material are attracting attention. Plants grow by absorbing carbon dioxide in the atmosphere, so even if paper derived from plants is consumed, there is no increase or decrease in terms of carbon dioxide emissions into the atmosphere (neutral). Therefore, it is considered that carbon dioxide emissions (for plastic) can be reduced by using paper instead of plastic.

  Carbon dioxide emissions can be reduced the most if plastic can be completely replaced with paper, but not all paper can be used depending on the intended use. In that case, a part of the plastic is replaced with paper, or a composite container in which the deterioration in function due to the use of paper is compensated with plastic is used.

  For example, instead of a container made entirely of plastic, a container having a paper base at the center and an inner surface and an outer surface of the paper sandwiched between thin thermoplastic molded products can be exemplified. In this container, the plastic layer is thinned to reduce the total amount of plastic used, and the decrease in rigidity due to the thin plastic layer is compensated by the paper substrate in the center. In addition, the paper container in the retorting process is not covered by paper, but the paper is covered with plastic, and the connection between the inner and outer surfaces of the container is heat-sealed to prevent exposure of the end face of the paper. In addition, the paper container rippling phenomenon that occurs during drying is suppressed (see Patent Document 1).

However, in the case of such a three-layer composite container, if there is an air layer between the inner and outer thermoplastic molded articles, the heat insulation effect is enhanced, and the heat sterilization effect during retort treatment is significantly impaired. is there. With regard to retort processing conditions, it is possible to maintain the sterilization effect by increasing the heating temperature or extending the sterilization time, but there is a risk of impairing the quality of the contents. It will damage and reduce the product value. In addition, the air remaining between the inner and outer thermoplastic molded articles may expand due to heating during the retorting process, and the composite container may be deformed or damaged.
For this reason, it is important that the gas inside the composite container be sufficiently removed (degassed) when the inner layer and the outer layer are bonded.

For example, in Patent Document 2, as a means for degassing a gap between inner and outer thermoplastic plastic molded articles, pressure is applied from the inner side of the inner plastic molded article (for example, compressed air), or a male mold or a combination of compressed air and male mold is used. Has been proposed. In the case of pressurization using a male mold, the dimensions of the male mold are set smaller than the inner layer molded product so that the inner layer molded product is not damaged or damaged when the male mold is inserted inside the inner layer molded product. There is a need to. For this reason, a gap is generated between the male mold and the inner layer molded product, and sufficient deaeration cannot be performed.
In order to remove air from the gap between the inner and outer thermoplastic molded articles, it is necessary to provide a deaeration port. This is because there is no air escape path if it is completely sealed, but it is difficult to seal while applying pressure by degassing with compressed air, so it is inevitable that pressure will be lost, and the gap will be sufficiently removed. It is difficult to care. There is a similar problem in the combined use of compressed air and male type.

  Furthermore, there is a problem that the thinner the thermoplastic molded product of the inner and outer layers is, the easier it is that the plastic molded product is distorted or wrinkled during degassing (see FIG. 3).

The inventors obtained the following knowledge as a result of studying the wrinkle generation mechanism of such a composite container.
When the outer layer side thermoplastic molded article 1 is made thinner, its rigidity becomes lower, so that deflection occurs, and there is a portion that does not adhere to the inner side of the outer layer side thermoplastic molded article 1 just by inserting the intermediate substrate 2. I can do it. Specifically, as shown in FIG. 3 (i), a gap 24 is formed at the peripheral edge in the flange of the intermediate base material 2 and the outer layer side thermoplastic molded article 1, so that this deflection affects the bottom of the container. In particular, the intermediate substrate 2 and the outer layer side thermoplastic molded article 1 are separated from each other at the corners. If evacuation 25 is performed in this state, as shown in FIG. 3 (ii), the flange portion of the composite container remains pulled and wrinkles 22 are formed at the bottom.
Twists and wrinkles that rise from the composite container body rub against machines and other containers when the container is transported or transported, causing pinholes. Therefore, it is desirable to remove the air sufficiently so as not to cause twisting or wrinkling in the container during deaeration.

  In addition, since a wide variety of products are sold at stores today, it is important to differentiate from other products. As means for differentiating from other products, product (container) shapes can be cited in addition to printing designs, etc., and containers capable of realizing various shapes and manufacturing methods capable of producing such containers are desired. .

JP 2000-238759 A JP 58-52047 A

The present invention relates to a composite container in which different types of materials are encased in an inner layer and an outer layer plastic molded product to form a container shape as a whole, and in particular, a composite container suitable for retort processing of contents and a method for manufacturing the same The task is to do.
Specifically, the first problem of the present invention is to provide a composite container free from twisting and wrinkling of a plastic molded product that removes the gas staying between the inner layer and the outer layer and constitutes the inner and outer layers. is there.
The second object of the present invention is to provide a composite container that can accommodate various shapes and a method for manufacturing the same.
The third object of the present invention is to provide a composite container in which the amount of plastic material used is suppressed.

A first invention for solving the above-mentioned problems is an inner layer side thermoplastic molded article having a flange portion in an opening, an intermediate base material, and an outer layer side thermoplastic molded article having a flange portion in the opening. Are laminated in this order, and the flange part provided in the inner layer side thermoplastic molded article and the flange part provided in the outer layer side thermoplastic plastic article are thermally bonded to each other, and the intermediate substrate is sealed. (A) a step of inserting the intermediate base material inside the outer layer side thermoplastic molded article, and (b) an inner peripheral edge of the flange portion provided in the outer layer side thermoplastic plastic article and the intermediate portion. A step of thermally bonding the edge of the opening of the base material, (c) a step of inserting the inner layer side thermoplastic molded product inside the intermediate base material, and (d) the outer layer side thermoplastic resin. A step of heat-bonding a flange part provided in the plastic molded product and a flange part provided in the inner layer side thermoplastic plastic product except for a part thereof to make a composite container intermediate product; Removing the gas remaining between the outer layer side thermoplastic molded article and the inner layer side thermoplastic molded article, and (f) the outer layer side heat while keeping the entire intermediate product of the composite container under reduced pressure. All the flanges provided in the thermoplastic plastic molded product and the flanges provided in the inner layer side thermoplastic molded product are thermally bonded together, and the intermediate base material is composed of the outer layer side thermoplastic molded product and the outer layer side thermoplastic molded product. A method of manufacturing a composite container.
In addition to the above-mentioned invention, the second invention for solving the above-mentioned problems is characterized in that the intermediate base material includes an inner peripheral edge of a flange portion provided in the outer layer side thermoplastic molded article and an opening side of the intermediate base material. It is a manufacturing method of the composite container characterized by providing the ventilation | gas_flowing part which can remove the gas between the said outer layer side thermoplastics molded article and the said intermediate | middle base material after heat-bonding an edge.
A third invention for solving the above-mentioned problems is a method for manufacturing a composite container, in addition to the above-mentioned invention, wherein the intermediate substrate is composed of a plurality of members.

According to the present invention, (e) removing the gas remaining between the outer layer side thermoplastic molded article and the inner layer side thermoplastic molded article under reduced pressure on the entire composite container intermediate product, (f ) All the flanges provided in the outer-layer side thermoplastic molded product and the flanges provided in the inner-layer side thermoplastic molded product are all thermally bonded while keeping the entire composite container intermediate product under reduced pressure, and the outer-layer side thermoplasticity A step of sealing the intermediate substrate with a plastic molded product and the outer layer side thermoplastic plastic molded product, so that a gap between the outer layer side thermoplastic molded product and the outer layer side thermoplastic plastic molded product is provided. The remaining gas can be removed sufficiently, preventing damage to the container during retort processing, and exhibiting sufficient sterilization effect by retort processing It can be obtained kill composite container.
In addition, since (b) a step of thermally bonding the inner peripheral edge of the flange portion provided in the outer layer side thermoplastic molded article and the opening edge of the intermediate substrate is provided, the outer layer side thermoplastic plastic molded article and The intermediate base material is fixed in close contact with each other, and slack can be minimized. Therefore, generation | occurrence | production of wrinkles and wrinkles on the outer layer side by subsequent deaeration can be suppressed.
Furthermore, in addition to the above effects, the intermediate base material is provided with a ventilation portion capable of removing gas between the outer layer side thermoplastic molded article and the intermediate base material. When left under reduced pressure, the gas left between the outer layer side thermoplastic molded article and the intermediate substrate is quickly removed, so it is possible to better suppress the occurrence of twisting and wrinkling on the outer layer side. .
Furthermore, since the intermediate base material is composed of a plurality of members, in addition to the above effects, it is possible to deal with complex shaped composite containers. Moreover, the followability of the intermediate base material with respect to the outer layer side thermoplastic plastic molded article is improved, and the adhesiveness between the two is increased. Therefore, generation | occurrence | production of wrinkles and wrinkles on the outer layer side can be further suppressed.

It is a cross-sectional schematic diagram which shows an example of the composite container which concerns on this invention. It is sectional drawing which shows typically an example of the manufacturing method of the composite container which concerns on this invention. It is sectional drawing which shows the manufacturing process of a composite container typically. It is sectional drawing which shows the manufacturing process of a composite container typically. It is a schematic diagram which shows the some example of the composite container which concerns on this invention. It is a schematic diagram which shows the some example of the composite container which concerns on this invention. It is a schematic diagram which shows the some example of the composite container which concerns on this invention.

An embodiment according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic sectional view showing an embodiment of a composite container according to the present invention. The composite container according to the present invention includes an intermediate base material 2, an outer layer side thermoplastic molded product 1 and an inner layer side thermoplastic plastic molded product 3 mainly composed of thermoplastic plastic. Each member has a flange portion 4 at the opening, and the length of the flange portions of the outer layer side thermoplastic molded product 1 and the inner layer side thermoplastic molded product 3 is longer than the length of the flange portion of the intermediate substrate 2. In order to securely seal the intermediate substrate 2, the flange dimension difference 23 is preferably 3 mm or more.

  The outer layer side thermoplastic molded article 1 and the inner layer side thermoplastic molded article 3 are both members made of thermoplastic plastic as a main raw material. The sheet material used for the thermoplastic molded article is not particularly limited, and examples thereof include a single-layer polypropylene having retort resistance, and a laminate with nylon or eval having gas barrier properties. An appropriate material can be selected according to various properties required for the container. The sheet thickness is preferably about 60 to 250 μm although it depends on the container shape.

  As an example of the manufacturing method of the outer layer side thermoplastic molded article 1 and the inner layer side thermoplastic molded article 3, there is a method using a vacuum / pressure forming machine. The thermoplastic sheet is heated sufficiently in the sheet heating section (using the radiant heat of the heater such as far infrared rays), and then the outer layer is formed by molding along the mold using compressed air and vacuum in the molding section. A side thermoplastic molded article 1 and an inner layer thermoplastic molded article 3 can be obtained.

  The intermediate substrate 2 may support a molded product of inner and outer layers made of thermoplastic plastics and may be a material resistant to heat, such as paper, metal foil, thin wood, thermosetting plastic, etc. Among them, paper is preferable from the viewpoint of recycling suitability and carbon neutral. By using paper as an intermediate substrate, it is possible to select a microwave oven as a means for reheating the contents, and since it is light and has appropriate heat insulation, the composite container can be used as it is after reheating the contents. When used as tableware, there are advantages such as being hard to feel even if the container body is directly held by hand, easy to process, capable of printing, and good design characteristics.

When paper is used as the intermediate substrate, for example, a paperboard is punched to adjust the shape, and this is assembled into the shape of the composite container. Examples of the shape of the composite container include a cylindrical shape, a cup shape, and a circular or square deep dish shape. The intermediate base material used for one composite container is composed of a plurality of members that are not bonded to each other even if they are all connected as shown in the developed view, and are shaped by folding or bending. It may be combined to form a container shape (see FIG. 7 (i)). Further, the intermediate substrate does not have to be disposed on the entire container, for example, a circular intermediate substrate is disposed only on the bottom surface of the bowl-shaped container, or a sheet-shaped intermediate substrate is disposed only on the side surface of the rectangular container. They may be arranged (see FIGS. 6 (G), (H) and FIG. 7 (R)). When assembling the intermediate base material cut into a predetermined shape into the shape of the composite container, gluing may be performed. In the outer layer side thermoplastic molded article 1 in the step (a) described later directly without gluing. You may arrange in. In the case of a container having many curved surfaces such as a hemisphere, a pulp mold container in which a paper substrate is three-dimensionally formed as an intermediate substrate can be used. In FIG. 1, the intermediate base material also includes the flange portion, but the intermediate base material may have no flange portion. Further, the flange portion does not have to be parallel to the bottom surface, and may be any configuration as long as the intermediate base material can be sealed with a thermoplastic molded product on the outer layer side and the inner layer side (see FIG. 7 (N)).
Further, the intermediate substrate may be a plurality of layers bonded or not bonded to each other. In this case, all the intermediate base materials may be thermally bonded to the outer layer side thermoplastic molded article in the step (b), but the innermost intermediate base material and the outer layer side flange may be bonded.

As the paperboard, coated paper, virgin paper or the like, and laminated paper obtained by laminating a thermoplastic resin such as polyethylene or polypropylene on these patterns can be preferably used.
The paperboard used as the intermediate substrate preferably has a paper basis weight of 180 g / m ² or more in order to give the composite container rigidity. Inner / outer layer thermoplastic molding using pressurization and heating during separate processes or retort treatment by using laminated paper laminated with thermoplastic resin or by applying heat seal varnish to the surface of paperboard in advance The product and the intermediate substrate can be bonded together.
When using a composite container as a retort food container, the composite container needs to have light-shielding properties. In this case, it is preferable to select a light-shielding material as the intermediate substrate.

The intermediate substrate 2 is preferably equal to or slightly smaller than the inner dimension of the outer layer side thermoplastic molded article 1, and the difference is preferably within 0.5%. If it is larger than this, the intermediate base material 2 will not fit in the outer layer side thermoplastic molded article 1, and if it is smaller, wrinkles will occur or the container will be deformed.
Further, the inner layer side thermoplastic molded article 3 is preferably equal to or slightly smaller than the inner dimension of the intermediate substrate 2, and the difference is preferably within 0.5%. If it is larger than this, the inner-layer side thermoplastic molded article 3 will not fit in the intermediate base material 2, and if it is smaller, it will cause wrinkles or deformation of the container.

FIG. 2 is a cross-sectional view schematically showing an example of a method for manufacturing a composite container according to the present invention.
First, the outer layer side thermoplastic molded article 1 is inserted into the female mold 5 (see FIG. 2 (A)). Here, the female mold 5 serves to hold the outer-layer-side thermoplastic molded article 1 and suppress a deviation from the intermediate base material 2 to be inserted later.
The outer layer side thermoplastic molded article 1 is preferably equal to or slightly smaller than the inner dimension of the female mold 5, and the difference is preferably within 0.5%. If it is larger than this, the outer layer side thermoplastic molded article 1 will not fit in the female mold 5, and if it is smaller, it will cause wrinkles or cause deformation of the container.

  FIG. 3 shows a conventional process for manufacturing a composite container, in which the inner layer side thermoplastic molded article 3 and the intermediate base material 2 are first bonded, and then the outer layer side thermoplastic plastic molded article 1 is placed outside the intermediate base material 2. Is shown, and a state of trying to deaerate between the inner and outer layer thermoplastic molded articles is shown. FIG. 3 (i) is a schematic diagram showing the arrangement and before deaeration, and FIG. 3 (ii) is a schematic diagram showing a state in which the wrinkles 22 are generated after the deaeration by the vacuuming 25.

  On the other hand, FIG. 4 (i) shows the manufacturing method of the present invention, and after placement, the inner peripheral edge of the flange portion provided in the outer layer side thermoplastic plastic molded article 1 and the opening edge of the intermediate substrate 2 are thermally bonded. After performing the step, the inner layer side thermoplastic molded article 3 is arranged inside the intermediate base material 2, and the flange portion provided in the outer layer side thermoplastic molded article 1 and the flange provided in the inner layer side thermoplastic molded article 3 are provided. FIG. 4 (ii) is a schematic diagram showing the state after deaeration in a state where a part is thermally bonded except for a part to obtain a composite container intermediate product. FIG. 4 (ii) schematically shows a state in which wrinkles are not generated and the intermediate base member 2 and the peripheral edge in the flange of the outer-layer side thermoplastic molded article 1 are in close contact with each other.

In the step (b), the optimum dimension of the gap 24 at the peripheral edge in the flange varies with the material of the outer-layer side thermoplastic molded article 1 and the intermediate base material 2 and varies depending on the container shape, container size, etc. The following is preferable. If it is more than this, the deflection at the bottom of the outer-layer side thermoplastic molded article 1 and the intermediate substrate 2 will increase, making it difficult to prevent wrinkles even by the production method of the present invention.
By using the female mold 5, even if the outer layer side thermoplastic molded article 1 is thinly formed, it is possible to compensate for the reduction in rigidity and prevent the occurrence of deflection with the intermediate base material 2.

Next, the intermediate base material 2 is inserted inside the outer layer side thermoplastic molded article 1 (step (b)), and the inner peripheral edge of the flange portion provided in the outer layer side thermoplastic plastic article 1 and the opening of the intermediate base material 2 The part edges are thermally bonded (see step (b) and FIG. 2 (b)).
For example, the first flange seal bar 6 is used for heat bonding between the inner peripheral edge of the flange portion provided in the outer layer side thermoplastic molded article 1 and the opening edge of the intermediate base, and the entire periphery is heat bonded (seal). To do. Here, the inner peripheral edge of the flange portion included in the outer layer side thermoplastic molded article 1 is a position in contact with the outermost periphery of the intermediate substrate 2. That is, the opening edge of the intermediate substrate is the outermost periphery of the intermediate substrate.
At least the inner peripheral edge of the flange portion of the outer-layer-side thermoplastic molded article 1 and the opening edge of the intermediate base material 2 are thermally bonded to each other. Can be prevented. At this time, if a part of the inner peripheral edge of the flange provided in the outer layer side thermoplastic molded article 1 and a part of the edge of the opening of the intermediate substrate 2 are bonded, there is an effect of preventing slippage, By heat-bonding around the entire circumference, wrinkles can be prevented more reliably.

The outermost periphery of the intermediate base material 2 is sealed with the intermediate base material with respect to the outermost periphery of the outer layer side thermoplastic molded article 1 and the inner layer side thermoplastic plastic molded article 3. Designed somewhat refraining so that you can touch. At this time, it is designed so that the outermost periphery of the intermediate base material 2 is on the inner side of about 3 mm with respect to the outermost periphery of the outer layer side thermoplastic molded product 1 and the inner layer side thermoplastic plastic molded product 3, and in step (b) Thus, it is preferable that the outermost periphery of the intermediate substrate 2 is thermally bonded to the inner peripheral edge of the flange portion of the outer layer side thermoplastic molded article 1 over the entire periphery.
Further, when the composite container has a shape having a flat flange portion whose angle with the side surface of the container is changed at the outermost periphery of the opening of the container, the flat flange included in the outer-layer side thermoplastic molded article 1 It is most preferable to thermally bond with the intermediate substrate 2 at the angle-switched portion which is the innermost side of the portion. Adhesion at the innermost side of the flat flange part minimizes the bump between the outer layer side thermoplastic molded article 1 and the intermediate base material 2 and suppresses warping and wrinkling at the time of deaeration in the subsequent process. be able to.

Next, the inner layer side thermoplastic molded product 3 is inserted inside the intermediate base material 2 (step (c)), and the outer layer side thermoplastic plastic molded product 1 has a flange portion and the inner layer side thermoplastic plastic molded product 3. Except for a part of the flange portion provided, it is thermally bonded to obtain a composite container intermediate product 11 (see step (d) and FIG. 2 (c)).
For example, the second flange seal bar 7 is used for thermal bonding between the flange portion provided in the outer layer side thermoplastic molded article 1 and the flange portion provided in the inner layer side thermoplastic molded article 3, and a part of the flange portion is provided with thermal bonding ( Seal). Here, the gas is removed in a later step from the partially left opening. The intermediate base material 2 and the inner layer side thermoplastic plastic molded product 3 are fixed in close contact with each other, and the outer layer side thermoplastic plastic molded product 1 and the inner layer side thermoplastic plastic molded product 3 do not deviate when degassing in the next step. It only has to be heat-bonded. Therefore, there may be a plurality of openings left to be thermally bonded. Further, since the flange portion is thermally bonded again in a later step, the thermal bonding here may be temporarily fixed.

Subsequently, the composite container intermediate product 11 is entirely removed under reduced pressure by removing the gas remaining between the outer layer side thermoplastic molded article 1 and the inner layer side thermoplastic plastic molded article 3 (step (e)). The flange part of the outer layer side thermoplastic molded article 1 and the flange part of the inner layer side thermoplastic molded article 3 are all thermally bonded while keeping the whole under reduced pressure, and the outer layer side thermoplastic molded article 1 and the outer layer side The intermediate substrate 2 is sandwiched and sealed with the thermoplastic plastic molded product 3 (see step (f), FIG. 2 (d)).
As a method for keeping the entire composite container intermediate product 11 under reduced pressure, for example, the composite container intermediate product 11 is composed of the female mold 5 and the sealing lid 8 that is combined with the female mold 5 and can seal the composite container intermediate product 11. The method of sealing is mentioned. In this case, for example, an air intake hole and a vacuum pump connected to the air intake hole are connected to the airtight lid 8, and the airtight space is decompressed by exhausting from the airtight space 9 formed by the female mold and the airtight lid. it can. Since the composite container intermediate product 11 has an unsealed portion between the flange portion provided in the outer layer side thermoplastic molded product 1 and the flange portion provided in the inner layer side thermoplastic molded product 3, the internal gas is removed therefrom. .
At this time, the pressure in the sealed space may be −0.05 MPa or less with respect to the external atmospheric pressure, and the lower the pressure, the more preferable it is because the gas held between the inner and outer thermoplastic molded articles can be removed. .

With respect to deaeration inside the composite container intermediate product 11, there is a possibility that the intermediate substrate 2 may be sucked by a method of evacuating the unsealed portion of the composite container intermediate product 11. Further, since suction can be performed only from one direction, there is a risk of causing wrinkles and deformation.
However, according to the method of the present invention, since the entire composite container intermediate product 11 is put in a sealed container and kept under reduced pressure, the intermediate base material 2 is not biased, and a plurality of unsealed portions are provided to provide gas. The flow is dispersed and can be quickly degassed, and wrinkles and deformation can be suppressed.
In addition, there is a method of discharging the internal gas by increasing the atmospheric pressure outside the composite container intermediate product 11, but such a pressurization method requires a large apparatus. On the other hand, when pressure reduction (evacuation) is performed in a sealed container, the pressure resistance required for the apparatus is about 0.1 MPa, which can be simple and inexpensive.

For example, a third flange seal bar 10 is used for heat bonding between the flange portion of the outer layer side thermoplastic molded article 1 and the flange portion of the inner layer side thermoplastic molded article 3, and the entire circumference is thermally bonded (sealed). To do. Since the composite container intermediate product 11 needs to maintain a reduced pressure state even during thermal bonding, for example, a third flange seal bar 10 that can be operated from the outside of the sealing lid 8 is provided on the sealing lid 8 side.
As described above, according to the present invention, the composite container 12 can be manufactured.

5 to 7 are schematic views showing a plurality of examples of the composite container according to the present invention. According to the present invention, composite containers having various shapes can be manufactured. Various shapes of composite containers can be manufactured by changing the shapes of the outer layer side thermoplastic molded article 1, the inner layer side thermoplastic molded article 3 and the intermediate substrate 2.
5 (e) is a cylindrical container, FIG. 5 (f) is a tapered cup-shaped container, FIG. 6 (g) is a container in which an intermediate base material is not disposed on some side surfaces, and FIG. 6 (h) is only on a side surface. A container in which an intermediate base material is arranged, FIG. 7 (R) is an example of a container in which an independent intermediate base material is arranged for each side surface. FIG. 7 (nu) is an example of a container having no flat flange at the opening.

PP outer layer side thermoplastic molded product uses PP total thickness of 200μm and inner layer side thermoplastic plastic molded material uses PP / EVOH / PP total thickness of 200μm, and intermediate substrate is coated with thermoplastic adhesive on both sides A composite container was prepared according to the production method of the present invention using the paper substrate having a thickness of 270 g / m ² . (PP: Polypropylene resin, EVOH: Eval resin)

A sheet-like thermoplastic having a total PP thickness of 200 μm was molded by a vacuum / pressure forming method, and an outer layer side thermoplastic molded product having a shape shown in FIG. Also, a sheet-like thermoplastic having a total PP / EVOH / PP thickness of 200 μm is molded by a vacuum / pressure forming method as in the case of the outer-layer-side thermoplastic molded article, and the inner-layer-side thermoplastic having the shape shown in FIG. A plastic molded product was produced. Furthermore, a paper base material having a thickness of 270 g / m ² coated with a thermoplastic adhesive on the front and back was punched into a predetermined shape and bent to produce an intermediate base material having the shape shown in FIG.

First, the outer layer side thermoplastic plastic molded product is inserted into a female mold corresponding to the shape of the molded product. The outer layer side thermoplastic molded product is slightly smaller than the inner size of the female mold, and the difference is 0.3%.
Next, the paper intermediate substrate is inserted inside the outer layer side thermoplastic molded article, and the width is 3 mm from the innermost part of the flat flange portion of the outer layer side thermoplastic molded article to the outside. Then, a hot plate having a surface temperature of 170 ° C. was pressed at a pressure of 0.5 MPa for 6 seconds to thermally bond the intermediate substrate and the flange portion of the outer layer side thermoplastic molded product. At this time, the gap dimension 24 described in FIG. 3 was 3 mm or less.

Thereafter, the inner layer side thermoplastic molded article is inserted inside the intermediate substrate, and a hot plate having a surface temperature of 180 ° C. is pressed against the flange portion at a pressure of 0.5 MPa for 5 seconds, and the outer layer side thermoplastic molded article and The flange portion of the inner layer side thermoplastic molded product was thermally bonded on the three sides of the composite container to obtain an intermediate product of the composite container.
This composite container intermediate product is placed in a female mold, and a sealing lid is placed on the female mold. That is, the composite container intermediate product is hermetically sealed by the female mold and the sealing lid that can be combined with the female mold to seal the composite container intermediate product. An air suction hole and a vacuum pump connected to the suction hole are connected to the hermetic lid, and exhausted from the hermetic space formed by the female mold and the hermetic lid, so that the hermetic space becomes zero with respect to the atmospheric pressure outside the hermetic container. The pressure is reduced to 0.05 MPa. Since the composite container intermediate product has one side of the flange portion that is not thermally bonded, the gas inside the intermediate product is removed from here.

  After deaeration, while maintaining the reduced pressure in the sealed container, heat bonding is performed by pressing a 180 ° C hot plate at a pressure of 0.5 MPa for 5 seconds to the flange on one side where heat bonding is not performed. The intermediate substrate is sandwiched between the thermoplastic molded product and the inner-layer side thermoplastic molded product, and completely sealed. By manufacturing the composite container through the above steps, a composite container free from twists and wrinkles could be obtained.

  For comparison, first, the inner layer side thermoplastic molded product is inserted inside the intermediate base material, and the flange portion of the intermediate base material and the inner layer side thermoplastic plastic molded product is thermally bonded with a hot plate, and then the intermediate material An outer layer side thermoplastic molded article is arranged outside the base material, and three sides of the flange portion of the inner layer side thermoplastic molded article and the outer layer side thermoplastic molded article are thermally bonded, and the same as in the embodiment. After removing the air remaining under reduced pressure, the flange part of the remaining one side was thermally bonded with a hot plate, and the intermediate base material was sandwiched between the outer layer side thermoplastic molded product and the inner layer side thermoplastic molded product, and sealed. A composite container was manufactured. However, in the state before deaeration, the gap 24 at the peripheral edge in the flange shown in FIG. 3 (i) is larger than 3 mm, and the bottom portion of the obtained composite container seems to have been affected by the deviation derived from the gap. The wrinkles that have been made.

DESCRIPTION OF SYMBOLS 1 ... Outer layer side thermoplastic molding 2 ... Intermediate base material 3 ... Inner layer side thermoplastic molding 4 ... Flange part 5 ... Female die 6 ... First flange seal bar 7 ... Second flange seal bar 8 ... Sealing lid 9 ... Depressurized space (inside the sealed chamber)
10. ・ 3rd flange seal bar 11 ・ Composite container intermediate product 12 ・ ・ Composite container 21 ・ ・ Paper container end face protective seal 22 ・ ・ Wrinkle 23 ・ ・ Flange size difference 24 ・ ・ Gap 25 around the flange inner edge ・ ・Evacuation

Claims (3)

An inner layer side thermoplastic molded product having a flange portion at the opening, an intermediate base material, and an outer layer side thermoplastic molded product having a flange portion at the opening are laminated in this order, and the inner layer side thermoplastic molding A flange part provided in a product and a flange part provided in the outer layer side thermoplastic molded product are thermally bonded to each other, and the intermediate base material is sealed.
(A) inserting the intermediate substrate inside the outer layer side thermoplastic molded article;
(B) a step of thermally bonding the inner peripheral edge of the flange portion provided on the outer layer side thermoplastic molded article and the opening edge of the intermediate base;
(C) inserting the inner layer side thermoplastic molded article inside the intermediate substrate;
(D) a step of heat-bonding a flange portion provided in the outer layer side thermoplastic molded product and a flange portion provided in the inner layer side thermoplastic plastic product except for a part thereof to obtain a composite container intermediate product;
(E) removing the gas remaining between the outer layer side thermoplastic molded article and the inner layer side thermoplastic molded article under reduced pressure of the entire composite container intermediate product;
(F) All the flanges provided in the outer-layer side thermoplastic molded product and the flanges provided in the inner-layer side thermoplastic molded product are all thermally bonded while keeping the entire composite container intermediate product under reduced pressure, Sealing the intermediate substrate with a thermoplastic molded article and the outer-layer thermoplastic molded article,
A method for producing a composite container, comprising:   The intermediate base material is formed by thermally bonding the inner peripheral edge of the flange portion included in the outer layer side thermoplastic plastic molded product and the opening edge of the intermediate base material, and then the outer layer side thermoplastic plastic molded product and the intermediate base. The method for producing a composite container according to claim 1, further comprising a ventilation portion capable of removing gas between the material and the material.   The method for manufacturing a composite container according to claim 1, wherein the intermediate base material includes a plurality of members.

Images